JP2586273Y2 - Electromagnetic solenoid - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic solenoid which can be suitably used for driving a proportional pressure control valve.

[0002]

2. Description of the Related Art A typical prior art is disclosed in, for example,
-80172 (Japanese Utility Model Application No. 1-141964). The prior art, as shown in simplified form in FIG. 5, there is an electromagnetic solenoid 3 for controlling the control pressure of the proportional pressure control valve 1, the primary pressure input from the entry side ports P _IN, Two outgoing ports P _out 1
Alternatively, in order to obtain a desired secondary pressure from P _OUT 2, a solenoid base 7 slidably housed a plunger 6 for driving a spool 4 built in the proportional pressure control valve 1 via a drive shaft 5, and a solenoid. A coil unit 8 detachably provided on the outer periphery of the base 7, a magnetic path component 9 surrounding the outer periphery of the coil unit 8, and a part of the magnetic path component 9; at least one of the coil units 8 An annular adjusting member is provided between the coil unit 8 and the receiving member 10 on the solenoid base 7 side in contact with the annular end surface. By replacing this annular adjusting member 11 with one having a different magnetic passage cross-sectional area,
If the maximum attraction force for the control current is insufficient by changing the magnetic attraction force of the solenoid, the annular adjusting member 11
Is replaced by a magnetic path cross-sectional area having a large cross-sectional area to increase the generated attractive force for the control current, and the annular adjusting member 11 is replaced by a magnetic path having a small cross-sectional area to reduce the generated attractive force against the control current. It is configured to be able to.

[0003]

In such a prior art, the electromagnetic solenoid 3 is integrated by accumulating dimensional tolerances of components constituting the proportional pressure control valve 1 and the electromagnetic solenoid 3.
The operating point fluctuates in the secondary pressure with respect to the control current, and the hysteresis as a static characteristic and the operating stability as a dynamic characteristic also fluctuate.The same control current excites the solenoid. However, there is a problem that the secondary pressure varies due to machine differences.

Accordingly, it is an object of the present invention to provide an electromagnetic solenoid capable of minimizing a variation in a secondary pressure with respect to a control current.

[0005]

SUMMARY OF THE INVENTION The present invention has an electromagnetic coil and a plunger inserted in the electromagnetic coil so as to be displaceable in an axial direction, and corresponds to a magnitude of a current for exciting the electromagnetic coil. In an electromagnetic solenoid that generates a magnetic attraction force and drives the plunger to be displaced in the axial direction, a magnetic shielding member and a magnetic path constituting member 44a, 44 made of a non-magnetic material are provided between the electromagnetic coil and the plunger.
The electromagnetic solenoid is characterized in that a tube 44 constituted by b is interposed movably in the axial direction.

[0006]

According to the present invention, a tube 44 composed of a magnetic shielding member made of a non-magnetic material and magnetic path constituting members 44a and 44b is interposed between the plunger of the electromagnetic coil and the plunger so as to be displaceable in the axial direction. Such a tube 44
Can be adjusted in the axial direction to adjust the number of lines of magnetic force passing through the plunger, thereby adjusting the attraction to the plunger with respect to the control current without changing the magnetic path cross-sectional area. The displacement of the operating point due to the machine difference can be reduced.

[0007]

FIG. 1 is a sectional view showing an embodiment of the present invention. The spool 2 is provided on the casing 24 of the proportional pressure control valve 23 driven by the electromagnetic solenoid 21 of the present embodiment.
5 is formed so as to be slidable in the axial direction thereof, and a spool 25 in the valve hole 26 is provided with a spring receiving piece 2.
The spring receiving piece 28 is resiliently pressed by the first spring 29 supported by the spring 8, and is screwed into the screw hole 27.

The spool 25 has an axial hole 30 extending in the axial direction and first to third axial holes formed at intervals in the axial direction.
Annular grooves 31a, 31b, 31c, a first diameter hole 33a communicating the shaft hole 30 and the first annular groove 31a in the diameter direction, and a second hole communicating the shaft hole 30 and the outer peripheral surface of the spool 25. It has a two-diameter hole 33b.

An electromagnetic solenoid 21 is mounted on the casing 24, and a mounting hole 34 communicating with the valve hole 26 is formed. An annular receiving member 35 is formed in the mounting hole 34.
It is mounted in an airtight state by a ring 36 and the mounting hole 34
By screwing an external screw 39 formed on the outer peripheral surface of the casing 38 to an inner screw 37 formed on the inner peripheral surface near the opening end of the casing 38, the opening end 40 of the substantially bottomed cylindrical casing 38 is screwed. Thereby, the receiving member 35 is pressed and stopped.

An electromagnetic coil 41 is accommodated in the casing 38. The electromagnetic coil 41 has a magnetic path constituting member 4 accommodating a plunger 43 made of a ferromagnetic material such as iron.
4a and 44b (hereinafter collectively referred to as 44) are inserted. An insertion hole 46 through which a drive shaft 45 screwed to the plunger 43 is inserted is formed at one axial end of the magnetic path constituting member 44, and is fixed by a portion surrounding the insertion hole 46 and the receiving member 35. Configure the magnetic pole. This insertion hole 46 is a storage hole 47 in which the plunger 43 is stored.
And is movably inserted in the axial direction along the storage hole 47. At one end where the insertion hole 46 is formed, a truncated cone-shaped inclined surface 49 is formed facing the storage hole 47, and the plunger 43 is substantially parallel to the inclined surface 49.
A truncated cone-shaped inclined surface 50 is formed at one end in the axial direction.

An outer screw 51 is formed on a part of the outer peripheral surface of the magnetic path constituting member 44. The outer screw 51 is screwed into the inner screw 53 of the casing 38 and is prevented from being removed by a lock nut 54. At the other end of the magnetic path component 44 in the axial direction, a engaging portion 55 to which a tightening tool such as a wrench is engaged is formed, and the magnetic path component 44 is moved to the casing 38 with the lock nut 54 loosened. Therefore, the relative positions of the magnetic path constituting member 44 and the magnetic shielding member 61 with respect to the electromagnetic coil 41 can be adjusted in the axial direction.

A screw hole 56 is formed in the engaging portion 55, and an adjusting bolt 57 is screwed into the screw hole 56, and the spring receiving piece 58 is moved forward / backward in the axial direction to move the second spring 5
9 can be adjusted. Adjustment bolt 57
Is stopped by the lock nut 60.

An annular magnetic shielding member 61 made of a non-magnetic material such as stainless steel is interposed at an intermediate position in the axial direction of the magnetic path constituting member 44.
The inclined surface 50 of the plunger 43 faces radially inward of the magnetic shielding member 61. Therefore, a magnetic circuit is formed radially inward, avoiding the magnetic shielding member 61, as shown by the imaginary line 63, and the plunger 43 is moved by the large magnetic attraction force via the inclined surfaces 49, 50 without magnetic saturation. When the control current is applied to the electromagnetic coil 41 via the line 64, a large suction force can be obtained. A relatively large space is formed in the diameter direction between the inclined surfaces 49 and 50, and the magnetic circuit between the inclined surfaces 49 and 50 is formed in the axial direction. There is no danger that the friction will increase due to the one-sided suction toward the outside, so that it is possible to prevent the hysteresis from increasing.
Here, the term “outward in the radial direction” corresponds to a plane direction perpendicular to the plane of FIG. 1, and the term “axial direction” corresponds to the left-right direction in FIG. 1.

FIG. 2 shows the spool 2 of the proportional pressure control valve 23.
It is an expanded sectional view near 5. Wherein in the state of the electromagnetic solenoid 21 is energized, as shown in FIG. 2 (1), the spool is pushed by the solenoid to move to the left, the input port P _IN, output port P _OUT and the annular concave groove 31c communicated by and is blocked from the output port P _OUT and drain port P _D by an annular groove 31a, lands 67 formed between 31b. Therefore, the fluid, such as the primary pressure hydraulic oil, supplied to the input port P _IN is reduced in pressure to a predetermined secondary pressure from the output port P _OUT and discharged.

That is, the pressure (secondary pressure) P2 of the output port P _OUT at this time is obtained by setting the spring force of the first spring 29 to F1, the spring force of the second spring 59 to F2, and the cross-sectional area of the land 65. A2, the cross-sectional area of the land 67 is A1, and the suction force of the electromagnetic solenoid 21 is _FSOL .

[0016]

(Equation 1)

In the excited state, the electromagnetic solenoid 21
Since the attraction force F _SOL is proportional to the exciting current i, it is represented by F _SOL = K · i (2). Here, K is a force per unit current, and F _SOL = 0 in the above-mentioned non-excitation state. The secondary pressure P2 is determined by the suction force _FSOL , the difference between the spring forces F1 and F2 of the first and second springs, and the difference between the cross-sectional areas A2 and A1.

When the electromagnetic solenoid 21 is not excited, the spool 25 is displaced rightward as shown in FIG. 2 (2), and the input port P _IN and the output port P _OUT are cut off by the land 65. You. The output port P _OUT is connected to the drain port P _D, and P2 = 0.

FIG. 3 is a graph showing the relationship between the operating point displacement L of the spool 25 and the suction force _FSOL . As can be seen from the drawing, the suction force F _SOL can be changed with respect to the operating point displacement L of the spool 25.

FIG. 4 is a graph showing the relationship between the exciting current i and the secondary pressure P2. As described above, the lock nut 5
4 is displaced to displace the magnetic path constituting member 44 which is a fixed magnetic pole, for example, from the line L1 to the line L1.
2 or from line L2 to line L1. The first and second springs 29,
In the case of the adjustment by 59, the lines L1 and L2 only move in parallel in the vertical direction in FIG. 4, and the inclination cannot be changed.

As described above, the magnetic path constituting members 44, 61, and 44a are configured to be movable with respect to the casing 24, and the relative position can be adjusted from the outside, so that the operating point of the electromagnetic solenoid 21 can be easily adjusted from the outside. Can be set. Further, as described in connection with the prior art, there is no need to prepare a plurality of annular adjusting members 11 having different thicknesses in advance, and thus the configuration is simplified. Moreover, since the inclined surfaces 49 and 50 are formed on the plunger 43 and the magnetic path constituting member 44, the magnetic path cross-sectional area can be increased to avoid a magnetic saturation state.
A large suction force can be obtained without increasing the size of the configuration, thereby improving the responsiveness and obtaining a uniform secondary pressure.

In the above-described embodiment, the proportional pressure control valve 23 is driven by the electromagnetic solenoid 21. However, another configuration, for example, a directional control valve may be used, or the opening of the needle or the like is adjusted. May be used.

[0023]

As described above, according to the present invention, the tube 44 composed of the magnetic shielding member made of a non-magnetic material and the magnetic path constituting members 44a and 44b is displaced in the axial direction between the electromagnetic coil and the plunger. The operating point can be easily adjusted without excessively reducing the magnetic attraction force acting on the plunger, so that a large output of the plunger can be obtained. Is small and can be operated stably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electromagnetic solenoid 21 according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view near a spool 25.

FIG. 3 is a graph showing a relationship between an operating point displacement L of a spool 25 and a suction force _FSOL .

FIG. 4 is a graph showing a relationship between an exciting current i and a secondary pressure P2.

FIG. 5 is a simplified cross-sectional view of a typical prior art.

[Explanation of symbols]

Reference Signs List 21 electromagnetic solenoid 23 proportional pressure control valve 24 casing 25 spool 29 first spring 31a, 31b, 31c annular concave groove 33a, 33b diameter hole 41 electromagnetic coil 43 plunger 44, 44a magnetic path constituent member 49, 50 inclined surface 61 magnetic shielding member P _IN input port P _OUT output port

Claims (1)

(57) [Scope of request for utility model registration] An electromagnetic coil; and a plunger inserted into the electromagnetic coil so as to be displaceable in an axial direction. The plunger generates a magnetic attractive force corresponding to a magnitude of a current for exciting the electromagnetic coil. An electromagnetic solenoid for displacing and driving a plunger in an axial direction, wherein a magnetic shielding member and a magnetic path constituting member 44a, 4 made of a non-magnetic material are provided between the electromagnetic coil and the plunger.
An electromagnetic solenoid, wherein a tube 44 constituted by 4b is interposed so as to be displaceable in the axial direction.